This invention is in the field of reflector lamps, such as those which include the commonly known Parabolic Aluminized Reflector (PAR) lamp and the Reflector (R) lamp both used for floodlighting and as spotlights. In such lamps, the light source is recessed in a concave reflector which reflects frontwardly in a desired beam pattern substantially more than half of the total light output of the light source of the lamps.
PAR reflector lamps are disclosed in U.S. Pat. No. Re. 30,832 of F. F. LaGiusa, Reissued Dec. 22, 1981; U.S. Pat. Nos. 4,420,801 of G. H. Reiling et al and 4,420,800 of D. D. Van Horn; U.S. application Ser. Nos. 377,754 of D. D. Van Horn et al, filed May 13, 1982; and 517,193 of A. Munoz et al filed July 26, 1983, all of which are assigned to the assignee of the present invention.
U.S. patent application Ser. No. 349,334, now U.S. Pat. No. 4,420,800 discloses a reflector lamp comprising a finite light source positioned substantially at the focal point of a concave reflector. The concave reflector of such a lamp can be comprised of a front reflective surface which has a parabolic shape, an intermediate reflective surface which is spheroid, and a rear reflective surface which has a parabolic shape, all of which surfaces reflect light from the light source in a frontward manner. The front, intermediate and rear sections have a confocal point. The prior art reflector lamp further comprises a light source positioned at the confocal point of the concave reflector. Such a reflector lamp still further preferably comprises a lens positioned over the front of the reflector.
The prior art type of reflector lamp directs the emitted light into a desired beam pattern which is transmitted out of the lamp through the lens. Of the total lumens of light rays developed by the light source of the prior art reflector lamp, an undesirable amount of light rays are absorbed or disadvantageously reflected by the reflective surfaces of the reflector in such a manner so as to end up outside of the desired or main beam pattern and therefore these rays are considered unusable. These unusable rays are mainly wasted (1) by being undesirably and internally absorbed by the reflector, and (2) by being directed to areas within the reflector which when reflected by the internal surfaces of the lamp result in light rays which fall outside of the desired beam pattern. It is desired that a reflector lamp be provided which reduces the undesirable amount of lumens internally absorbed by the reflector and undesirably reflected by the internal surfaces of the reflector so as to improve the amount of useful light emitted by the reflector lamp. The overall effect of such a reflector would increase the percentage of the source of lumens that end up in the useful beam pattern.
Accordingly, objects of the present invention are to provide a more efficient reflector lamp with enhanced optical efficacy having, (1) a reduced amount of internal absorption, and (2) internal reflective surfaces that more advantageously direct the light rays into the useful beam pattern of the reflector lamp.
These and other objects of the present invention will become more apparent upon consideration of the following description of the invention.